18 is an adult in my books. Volunteer. It will give you something to do, people to meet, a sense of responsibility, and experience for your resume. With any luck, a position may turn into a paid one.

In the meantime, find ways to take responsibility and contribute in your home. 18 is old enough to pay rent, HOWEVER I understand how mental health can affect the ability to do so. There are other ways to contribute though and this too will eat away at the boredom.

If you can find a group to attend or even sign up for a class - pottery was my favourite.

You can do this.